Experimental confirmation of barrierless reactions between HeH+ and deuterium atoms suggests a lower abundance of the first molecules at very high redshifts

Experimental and theoretical investigation confirmed that the reaction between helium hydride ions (HeH+) and deuterium atoms is fast at low temperatures, which has implications for the abundance of the first molecules in the early universe. This suggests previous estimates, based on an older model with an artificial energy barrier, underestimated the reaction rate, potentially affecting models of early universe chemistry and star formation.

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This study provides experimental confirmation of recent theoretical work, improving our understanding of early universe chemistry. The experimental design is sound, and the combined experimental and theoretical approach strengthens the conclusions. No obvious flaws or limitations were identified.